^[a-zA-Z0-9.!#$%&'*+-/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:.[a-zA-Z0-9-]+)*$

also provides an API

"The really important kind of freedom involves attention and awareness and discipline, and being able truly to care about other people and to sacrifice for them over and over in myriad petty, unsexy ways every day. That is real freedom. That is being educated, and understanding how to think. The alternative is unconsciousness, the default setting, the rat race, the constant gnawing sense of having had, and lost, some infinite thing."

Plutarch: What we achieve inwardly will change outer reality Seneca: As is a tale, so is life: not how long it is, but how good it is, is what matters

Mark it one of two ways: "Not at this address," or "Addressee unknown." That'll get the post office to make a note of it and to discontinue the deliveries.

reverse whois

checking that the address really exists when it is entered by the user. First, it checks if the domain/host part exists at all, and reports an error if it does not. I found that this step alone catches between 1/2 and 2/3 of typos. Second, it tries to val

connects to the mail server and checks whether the mailbox exists or not

good reverse phone number lookup tool. wish it had a query param though so I could quicksearch from Firefox!

With this service you can create a temporary e-mail address that will forward all incoming mail to your usual e-mail address.

3950 Chesapeake Street NW, Washington, DC 20016

5500 Eads Street NE, Washington, DC 20019 202.724.4500

5511 Massachusetts Avenue, Bethesda, MD 20816 (301) 320-6515

3000 Cathedral Ave, NW, Washington, DC 20008 202.939.8800

101 T Street NE, Washington, DC 20002 202.529.4400

1601 R. Street SE, Washington, DC 20020

1300 Clifton Street NW, Washington, DC 20009-7099 202.673.7385

800 Euclid Street NW, Washington, DC 20001 202.673.7322

4300 C St. SE, Washington, DC 20019

10001 Ardwick-Ardmore Road, Springdale, Maryland 20774 (301) 636.8000

51 University Boulevard East, Silver Spring, Maryland 20901-2451 301.649.2800

4201 Stringfellow Road, Chantilly, VA 20151 703.222.8100

4095 Minnesota Avenue NE, Washington, DC 20019

3825 Wisconsin Avenue NW, Washington, DC 20016 202.537.8100

5000 14th Street, N.W. Washington, DC 20011 202.722.5555

7303 River Road, Bethesda, Maryland 20817 301.365.5300

7000 Adelphi Rd., Hyattsville, MD 20782-1454

4301 East-West Highway Bethesda, MD 20814

250 Richard Montgomery Drive, Rockville, Maryland 20852

4200 Davenport Street NW, Washington, DC 20016-4560

4101 Connecticut Avenue NW, Washington DC 20008

151 T Street NE, Washington, DC 20002-1519

12601 Dalewood Drive Wheaton, Maryland 20906

9525 Main St, Fairfax, VA 22031-4099

6560 Braddock Road, Alexandria, VA 22312

regexp-based address validation